In previous engines, one floating ember was enough to slow performance considerably; a shower of them was impossible. With Unreal Engine 4, there can be millions of such particles, as long as the hardware is potent enough to sustain them. Game developers overuse features of every new engine, because they are suddenly so easy to implement. In the original Unreal Engine, for example, the ability to render colored lighting led to a rash of games that employed the effect. The same may prove true for UE4′s particle effects, for better or worse. (“Mark my words,” Bleszinski says, “those particles are going to be whored by developers.”)

In one 153-second clip, the Epic team has packed all the show-off effects that have flummoxed developers for years: lens flare, bokeh distortion, lava flow, environmental destruction, fire, and detail in landscapes many miles away. Plus, it’s breathtakingly photo-realistic—or would be if demon knights were, you know, a real thing.

But that’s just the opening scene. After the cinematic, Epic’s senior technical artist, Alan Willard, starts playing the demo. At this point the view switches to that disembodied first-person perspective made so ubiquitous by shooting games like the Call of Duty franchise and Epic’s own influential Unreal titles. Willard maneuvers his avatar into a dimly lit room where a flashlight turns on, revealing eddies of dust—thousands of floating particles that were invisible until exposed. In another room, globes of various sizes float in the air. Willard rolls a light-emanating orb along the floor (think of a spherical flashlight that rolls like a bowling ball) and beams of light wobble and change direction, illuminating parts of the room and revealing the clusters of floating spheres with a kind of strobe effect. At first it all seems perfectly familiar: “Well, yeah,” you think, “that’s how they’d act in the real world. What’s the big deal?” But it is a big deal: This is stuff that videogames have never been able to simulate—the effects simply aren’t possible on today’s consoles.

1- the demo was made specifically to show what could not be done until now. And mostly that means totally dynamic lighting from a massive number of different sources. Screenshots don't show anything. What this means for devs is that they can build dynamic environments (read: destructible) without worrying about how shadows and lighting will look like when that torch that was on the wall is gone since the wall has come down.

2- next-gen consoles will at best be at the level of 80% of release-date-current top-of-the-line PCs. Which means as usual that within a couple of years most PCs will be more powerful. Within 5 years they become a joke, just like we've got now. What I'm really worried about is how the Epic guys are scared that we won't even reach the 80% power! More like 50% because they need to keep the costs down.

Which to me means only one thing: re-fragmentation of the gaming market, with the most advanced games coming on PCs, then consoles mass market and tablets just slightly behind. In fact tablets may well become indistinguishable from consoles at some point in the near future.